According to Southwest Airlines' policy, customer service agents must verify a child's age at the airport using a government-issued photo identification, but there is no regulation regarding matching last names of a child with the accompanying adult on domestic flights.

Airline officials said in a statement the company had contacted Ms Gottlieb and apologised "if our interaction made this family uncomfortable", the Washington Post reported.

"I do feel like as a white female, with a position of privilege, and a platform where someone is going to listen, it is my responsibility to say, 'hey, this happened, this isn't OK,'" she told CBS News.

"And maybe somewhere down the line, that helps my son, who is biracial and will be for his entire life."